Goyim gets mistaken for Jews. It happens. Everyone has a good laugh about it, eats some ham, and moves on.
Well, apparently, not everyone. Ethel Merman didn't exactly like being called Jewish. Supposedly, she got really pissy about it.
Oh, right, you probably don't even know who Ethel Merman is. Well, you might remember her from the role in "Airplane!" as Lieutenant Hurwitz (Jew?), the shell-shocked soldier who thinks he's Ethel Merman. (Everything is coming up roses!) Prior to that, she was a big deal, the leading lady of musical theater, starring on Broadway for five decades.
So why didn't she like being mistaken for Jewish? Who knows. But, on the other hand, it's not like we like to be mistaken for goyim.
Would we get pissy about it?
Get back to us on that one...